Suboptimal feedback control of TCP flows in computer network using random early discard (RED) mechanism

Abstract

We consider a dynamic model that simulates the interaction of TCP sources with active queue management system (AQM). We propose a modified version of an earlier dynamic model called RED. This is governed by a system of stochastic differential equations driven by a doubly stochastic point process with intensity as the control. The feedback control law proposed observes the router (queue) status and controls the intensity by sending congestion signals (warnings) to the sources for adjustment of their transmission rates. The (feedback) control laws used are of polynomial type (including linear) with adjustable coefficients. They are optimized by use of genetic algorithm (GA) and random recursive search (RRS) technique. The numerical results demonstrate that the proposed model and the method can improve the system performance significantly. Copyright © 2005 Hindawi Publishing Corporation.